SC196 1.5A Synchronous Buck Converter with …€¦ · 150 mV Output Voltage Range V OUT 0.8 V IN V...

February 8, 2007

The SC196 is a synchronous step-down converter with integrated power devices designed for use in applications using a single-cell Li-ion battery. Its wide input voltage range also makes it suitable for use in systems with fi xed 3.3V or 5V supply rails available. The switching frequency is nominally set to 1MHz, allowing the use of small inductors and capacitors. The current rating of the internal MOSFET switches allows a DC output current of 1.5A.

The output voltage is set by connecting a resistor divider from the fi lter inductor to the feedback pin. See the SC196A for pin-programmable output voltages.

The SC196 has a fl exible clocking methodology that allows it to be synchronized to an external oscillator or controlled by the internal oscillator. The device operates in either forced PWM mode or in PSAVE mode. If PSAVE mode is enabled, the part will automatically enter PFM at light loads to maintain maximum effi ciency across the full load range.

For noise sensitive applications, PSAVE mode can be disabled by synchronizing to an external oscillator or pulling the SYNC/PWM pin high. Shutdown turns off all the control circuitry to achieve a typical shutdown current of 0.1μA.

Cell phonesWireless communication chipset powerPersonal media playersMicroprocessor/DSP core/IO powerPDAs and handheld computersWLAN peripheralsUSB powered modems1 Li-Ion or 3 NiMH/NiCd powered devices

Up to 95% effi ciencyVOUT adjustable from less than 0.8V to VIN

Output current — 1.5AInput range — 2.5V to 5.5VQuiescent current — 17μAFixed 1MHz frequency or 750kHz to 1.25MHz synchronized operationPSAVE operation to maximize effi ciency at light loadsShutdown current <1μAFast transient response100% duty cycle in dropoutSoft-startOver-temperature and short-circuit protectionLead-free package — MLPD10-UT, 3 x 3 x 0.6 mm

COUT22μF

L14.7μH

VIN2.5V to 5.5V

VOUT<0.8V to VIN

1.5A

CIN10μF

VIN

EN

SYNC/PWM PGNDGND

MODE ADJ

SC196 LX

RFB1

RFB2

VOUTPVINCFB110pF

1 www.semtech.com

SC196 1.5A Synchronous Buck Converter

with Integrated Power Devices POWER MANAGEMENT

Features

Applications

Typical Application Circuit

Description

Unless otherwise noted: VIN = 3.6V, VOUT = 1.8V, EN = VIN, SYNC/PWM = VIN, MODE = VIN , TA = -40 to 85°C. Typical values are at TA = 25°C.

Parameter Symbol Conditions Min Typ Max Units

Input Voltage Range VIN 2.5 5.5 V

UVLO Threshold (upper) VUVL 2.18 2.3 2.45 V

UVLO Hysteresis VUVLHYS 150 mV

Output Voltage Range VOUT 0.8 VIN V

FB Voltage Tolerance VFB VIN = 2.5V to 5.5V, IOUT = 0mA to 1.5A 0.485 0.5 0.515 V

Load Regulation (PWM) VOUT LOAD IOUT = 0mA to 1.5A ±0.5 ±1 %

PSAVE Regulation VOUT PSAVESYNC/PWM=GND,COUT = 22μF,

VIN = 2.5V to 5.5V, IOUT = 0mA to 1.5A ±2 ±3 %

P-Channel Current Limit ILIM(P) VIN=2.5V to 5.5V 1.96 2.8 3.57 A

Quiescent Current IQSYNC/PWM = GND, IOUT = 0A,

VOUT = 1.04 x VOUT(Programmed)17 28 μA

Shutdown Current ISD EN = GND, LX = OPEN 0.1 1 μA

Exceeding the specifi cations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specifi ed in the Electrical Characteristics section is not recommended.

Parameter Symbol Maximum Units

Input Supply Voltage VIN -0.3 to 7 V

Logic Inputs (N=SYNC/PWM, EN, MODE) VN -0.3 to VIN+0.3, 7V Max V

Output Voltage VOUT -0.3 to VIN+0.3, 7V Max V

ADJ Input VADJ -0.3 to VIN+0.3, 7V Max V

LX Voltage VLX -1 to VIN +1, 7V Max V

Thermal Impedance Junction to Ambient(1) θJA 40 °C/W

VOUT Short-Circuit to GND tSC Continuous s

Operating Ambient Temperature Range TA -40 to +85 °C

Storage Temperature TS -65 to +150 °C

Junction Temperature TJ -40 to +150 °C

Peak IR Refl ow Temperature TPKG 260 °C

ESD Protection Level (2) VESD 2 kVNotes:(1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.(2) Tested according to JEDEC standard JESD22-A114-B.

Absolute Maximum Rating

Electrical Characteristics

2© 2007 Semtech Corp. www.semtech.com

SC196

PRELIMINARYPOWER MANAGEMENT

Parameter Symbol Conditions Min Typ Max Units

P-Channel On Resistance RDSP ILX = 100mA 0.275 Ω

N-Channel On Resistance RDSN ILX = 100mA 0.165 Ω

LX Leakage Current PMOS ILXP LX = GND, EN = GND 0.1 2 μA

LX Leakage Current NMOS ILXN LX = 3.6V, EN = GND -2 0.1 μA

Oscillator Frequency fOSC 0.85 1.0 1.15 MHz

SYNC Frequency (upper) fSYNCU 1.25 MHz

SYNC Frequency (lower) fSYNCL 750 kHz

Start-Up Time tSTART 5 ms

Thermal Shutdown TSD 145 °C

Thermal Shutdown Hysteresis TSD-HYS 10 °C

Logic Input High(1) VIH 1.2 V

Logic Input Low(1) VIL 0.4 V

Logic Input Current High(1) IIH -2 0.1 2 μA

Logic Input Current Low(1) IIL -2 0.1 2 μA

Electrical Characteristics (Cont.)

Note:(1) For EN, SYNC/PWM, MODE


SC196


Ordering InformationNotes:1) Lead-free packaging only. This product is fully WEEE and RoHS compliant.2) Available in tape and reel only. A reel contains 3000 devices.

DEVICE PACKAGE

SC196ULTRT(1)(2) MLPD-UT10 3x3x0.6

SC196EVB Evaluation Board

TOP VIEW

1

2

3

4

10

9

8

7

5 6

MLPD-UT: 3X3X0.6, 10 LEAD

PVIN

VIN

SYNC/PWM

EN MODE

LX

PGND

GND

VOUT ADJ

T

196yywwxxxx

yy = two digit year of manufactureww = two digit week of manufacture

xxxx = lot number

Pin Confi guration Ordering Information

Marking Information


SC196


Pin Descriptions

Pin # Pin Name Pin Function

1 PVIN Input supply voltage connection to switching FETs — connect the input capacitor between this pin and PGND directly.

2 VIN Input supply voltage for control circuits

3 SYNC/PWM Oscillator synchronization input. Tie to VIN for forced PWM mode or GND to allow the part to enter PSAVE mode at light loads. Apply an external clock signal for frequency synchronization.

4 EN Enable digital input; a high input enables the SC196, a low disables and reduces quiescent cur-rent to less than 1μA. In shutdown, LX becomes high impedance.

5 VOUT Regulated output voltage sense pin — connect to the output capacitor allowing sensing of the output voltage.

6 ADJ Output Voltage Adjust and feedback compensation pin - connect resistor divider between this pin and GND to set the desired output voltage level.

7 MODE MODE select pin — MODE = VIN to select 100% duty cycle function, MODE = GND to disable this function.

8 GND Ground

9 PGND Power Ground

10 LX Inductor connection to the switching FETs

T THERMALPAD

Pad for heatsinking purposes — not connected internally. Connects to ground plane usingmultiple vias.


SC196


ControlLogic

Plimit Amp

Current Amp

Nlimit Amp

OSC & Slope Generator

PWMComp

Error Amp500mV

Ref

MODE

ADJ

SYNC/PWM

EN

GND

PGND

LX

PVIN

8

9

10

1

56

2

7

3

4

PSAVEComp

VIN

VOUT

Block Diagram


SC196


SC196 Detailed Description The SC196 is a synchronous step-down Pulse Width Modulated (PWM), DC-DC converter utilizing a 1MHz fi xed-frequency current mode architecture. The device is designed to operate in a fi xed-frequency PWM mode across the full load range and can enter Power Save Mode (PSAVE), utilizing Pulse Frequency Modulation (PFM) at light loads to maximize effi ciency.

OperationDuring normal operation, the PMOS MOSFET is activated on each rising edge of the internal oscillator. Current feedback for the switching regulator uses the PMOS current path, and it is amplifi ed and summed with the internal slope compensation network. The voltage feedback loop uses an external feedback divider. The on-time is determined by comparing the summed current feedback and the output of the error amplifi er. The period is set by the onboard oscillator or by an external clock attached to the SYNC/PWM pin. The SC196 has an internal synchronous NMOS rectifi er and does not require a Schottky diode on the LX pin.

Output Voltage SelectionThe output voltage can be programmed using a resistor network connected from VOUT to ADJ to GND. The combined resistance of the divider chain should be greater than 10KΩ and less than 1MΩ. Table 1 lists appropriate resistors which limit the bias current required of the external feedback resistor chain and ensuring good noise immunity.

The output voltage can be adjusted between less than 0.8V and VIN. The output voltage formula is:

1RR5.0V

2FB

1FBOUT

VOUT = output voltage (V)RFB1 = feedback resistor from VOUT to ADJ (Ω)RFB2 = feedback resistor from ADJ to GND (Ω)

Resistors with 1% or better tolerance are recommended to ensure voltage accuracy.

Table 1 — Recommended ADJ Resistor Combinations

VOUT(V) RFB2(kΩ) RFB1(kΩ)

1 200 200

1.1 200 240

1.2 200 280

1.3 200 320

1.5 178 357

1.6 200 442

1.7 178 432

1.8 178 464

1.875 178 487

2.5 200 806

2.8 178 820

3 178 887

3.3 100 560

3.6 100 620

3.8 100 665

Continuous Conduction & Oscillator SynchronizationThe SC196 is designed to operate in continuous conduction, fi xed-frequency mode. When the SYNC/PWM pin is tied high the part runs in PWM mode using the internal oscillator. The part can be synchronized to an external clock by driving a clock signal into the SYNC/PWM pin. The part synchronizes to the rising edge of the clock.

Protection FeaturesThe SC196 provides the following protection features:

• Thermal Shutdown• Current Limit• Over-Voltage Protection• Soft-Start

Thermal ShutdownThe device has a thermal shutdown feature to protect the SC196 if the junction temperature exceeds 145°C. In thermal shutdown, the on-chip power devices are disabled, effectively tri-stating the LX output. Switching will resume when the temperature drops by 10°C. During this time,

Applications Information


SC196


if the output voltage decreases by more than 60% of its programmed value, a soft-start will be invoked. Current LimitThe PMOS and NMOS power devices of the buck switcher stage are protected by current limit functions. In the case of a short to ground on the output, the part enters frequency foldback mode, which causes the switching frequency to divide by a factor determined by the output voltage. This prevents the inductor current from "stair-casing".

Over-Voltage ProtectionOver-voltage protection is provided on the SC196. In the event of an over-voltage on the output, the PWM drive is disabled, effectively tri-stating the LX output. The part will not resume switching until the output voltage has fallen 2% below the regulation voltage.

Soft-StartThe soft-start mode is enabled after every shutdown cycle to limit in-rush current. In conjunction with the frequency foldback, this controls the maximum current during start-up. The PMOS current limit is stepped up through seven soft-start levels to the full value by a timer driven from the internal oscillator. During soft-start, the switching frequency is stepped through 1/8, 1/4, 1/2 and full internal oscillator frequency. The time at which these steps are made is controlled by the output voltage reaching predefi ned threshold levels. When the output voltage is within 2% of the regulation voltage, soft-start mode is disabled.

Power Save Mode OperationThe PSAVE mode may be selected by tying the SYNC/PWM pin to GND. Selecting PSAVE mode will enable the SC196 to automatically activate/deactivate operation at light loads, maximizing effi ciency across the full load range. The SC196 automatically detects the load current at which it should enter PSAVE mode. The SC196 is optimized to track maximum effi ciency with respect to VIN.

In PSAVE mode, VOUT is driven from a lower level to an upper level by a switching burst. Once the upper level has been reached, the switching is stopped and the quiescent current is reduced. VOUT falls from the upper to lower levels in this low current state as the load current discharges

the output capacitor. The burst-to-off period in PSAVE will decrease as the load current reduces.

The PSAVE switching burst frequency is controlled so that the inductor current ripple is similar to that in PWM mode. The minimum switching frequency during this period is limited to 650kHz.

The SC196 automatically detects when to exit PSAVE mode by monitoring VOUT . For the SC196 to exit PSAVE mode, the load must be increased, causing VOUT to decrease until the power save exit threshold is reached. PSAVE levels are set high to minimize the undershoot when exiting PSAVE. The lower PSAVE comparator level is set +0.7% above VOUT, and the upper comparator level at +1.5% above VOUT, with the exit threshold at -2% below VOUT.

If PSAVE operation is required, then a 22μF output capacitor must be used.

Figure 1 — Power Save Operation

VOUT

0.7%

1.5%

PSAVE Mode at Light Load PWM Mode at Medium/High Load

-2%

BURST OFF

Higher Load Applied

0 A

Inductor Current

Time

100% Duty Cycle OperationThe 100% duty cycle mode may be selected by connecting the MODE pin high. This will allow the SC196 to maintain output regulation under conditions of low input voltage/high output voltage conditions.

In 100% duty cycle operation, as the input supply drops toward the output voltage, the PMOS on-time increases linearly above the maximum value in fi xed-frequency operation until the PMOS is active continuously. Once

Applications Information (Cont.)


SC196


the PMOS is switched on continuously, the output voltage tracks the input voltage minus the voltage drop across the PMOS power device and inductor according to the following relationship:

VOUT = VIN - IOUT x (RDSP + RIND)

where VOUT = Output voltage VIN = Input voltage IOUT = Output current RDSP = PMOS switch ON resistance RIND = Series resistance of the inductor

Inductor SelectionThe SC196 is designed for use with a 4.7μH inductor. Where VOUT > 3.8V is required, a 10μH inductor is recommended. The magnitude of the inductor current ripple depends on the inductor value and can be determined by the following equation:

IN

OUT

osc

OUTL V

V1fL

VI

This equation demonstrates the relationship between input voltage, output voltage, and inductor ripple current.

The inductor should have a low DCR to minimize the conduction losses and maximize effi ciency. As a minimum requirement, the DC current rating of the inductor should be equal to the maximum load current plus half of the inductor current ripple as shown by the following equation:

2III L

L(PK) UT(MAX)O

Final inductor selection will depend on various design con-siderations such as effi ciency, EMI, size and cost. Table 2 lists the manufacturers of practical inductor options.

CIN Selection The source input current to a buck converter is non-continuous. To prevent large input voltage ripple, a low ESR ceramic capacitor is required. A minimum value of 10μF should be used for input voltage fi ltering, while a 22μF capacitor is recommended for improved input voltage fi ltering.

Table 1 — Recommended Inductors

Manufacturer/Part # Value(μH)

DCR(Ω)

Rated Current

(A)

Tolerance(%)

DimensionsLxWxH(mm)

BI TechnologiesHM66404R1 4.1 0.057 1.95 20 5.7 × 5.7 ×2.0

CoilcraftD01608C-472ML 4.7 0.09 1.5 20 6.6 × 4.5 × 3.0

TDKVLCF4020T- 4R7N1R2 4.7 0.098 1.24 30 4.0 × 4.0 × 2.0

Taiyo YudenLMNP04SB4R7N 4.7 0.050 1.2 30 5.0 × 5.0 × 2.0

TOKOD52LC 4.7 0.087 1.14 20 5.0 × 5.0 × 2.0

SumidaCDRH3D16 4.7 0.050 1.2 30 3.8 × 3.8 × 1.8

CoilcraftLPS3015 4.7 0.2 1.1 20 3.0 × 3.0 × 1.5

COUT Selection The internal compensation is designed to work with a certain output fi lter corner frequency defi ned by the equation:

OUTC CL2

1f

This fi lter has a single pole and is designed to operate with a minimum output capacitor value of 10μF. Larger output capacitor values will improve transient performance. If PSAVE operation is required, the minimum capacitor value is 22μF.

Output voltage ripple is a combination of the voltage ripple from the inductor current charging and discharging the output capacitor and the voltage created from the inductor current ripple through the output capacitor ESR. Selecting an output capacitor with a low ESR will reduce the output voltage ripple component, as can be seen in the following equation:

ΔVOUT(ESR) = ΔIL(RIPPLE) x ESRCOUNT

Capacitors with X7R or X5R ceramic dielectric are strongly recommended for their low ESR and superior temperature

Note: recommended Inductors do not necessarily guarantee rated perfor-mance of the part.



SC196


and voltage characteristics. Y5V capacitors should not be used as their temperature coeffi cients make them unsuitable for this application. Attention should be paid to the DC voltage characteristics of the ceramic capacitors to be used for both input and output. Parts with different case sizes can vary signifi cantly. For example a 22μF X5R 0805 capacitor with 3.6V DC applied could have a capacitance as low as 12μF. When a 1206 size part is used, the capacitance is approximately 20μF. Table 3 lists the manufacturers of recommended capacitor options.

Table 3 — Recommended Capacitors

Manufacturer/Part # Value(μF)

Rated Voltage (VDC)

TemperatureCharacteristic Case Size

MurataGRM21BR60J226ME39L 22 6.3 X5R 0805

MurataGRM422X5R226K16H533

22 16 X5R 1210

MurataGRM188R60J106 MKE19

10 6.3 X5R 0603

TDKC2012X5R0J106K 10 6.3 X5R 0603

Note: Where PSAVE operation is required, 22μF must be used for COUT.

Feed-Forward Compensation CapacitorA small 10pf compensation capacitor, CFB1 is required to ensure correct operation. This capacitor should be connected directly across feedback resistor RFB1. Capacitors with X7R or X5R ceramic dielectric are strongly recommended for their superior temperature characteristics.



SC196


PCB Layout Considerations Poor layout can degrade the performance of the DC-DC converter and can contribute to EMI problems, ground bounce and resistive voltage losses. Poor regulation and instability can result.

A few simple design rules can be implemented to ensure good layout:

Place the inductor and fi lter capacitors as close to the device as possible and use short wide traces between the power components.

1.

Route the output voltage feedback path away from the inductor and LX node to minimize noise and magnetic interference. Keep RFB1 and RFB2 close to the ADJ pin to avoid noise pickup.Maximize ground metal on the component side to improve the return connection and thermal dissipation. Separation between the LX node and GND should be maintained to avoid coupling of switching noise to the ground plane.Use a ground plane with several vias connecting to the component side ground to further reduce noise interference on sensitive circuit nodes.

2.

3.

4.

GND

VINLX

COUTGND

CIN

SC196

VOUT

LOUT

SYNC/PWMEN

MODE

RFB2 RFB1

GND

CFB1



SC196


Effi ciency vs. Load Current VOUT = 1.0V




PWM to PSAVE HysteresisEffi ciency vs. Input Voltage

Typical Characteristics

0

10

20

30

40

50

60

70

80

90

100

0.0001 0.001 0.01 0.1 1 10IOUT(A)

Effic

ienc

y (%

)

VIN=3.9V PSAVE

VIN=4.2V PSAVE

VIN=5.0V PSAVE

VIN=3.2V PWM

VIN=4.2V PWM

VIN=5.0V PWM

0

10

20

30

40

50

60

70

80

90

100

0.0001 0.001 0.01 0.1 1 10IOUT(A)

Effic

ienc

y (%

)

VIN=3.3V PSAVE

VIN=4.2V PSAVE

VIN=5.0V PSAVE

VIN=3.3V PWM

VIN=4.2V PWM

VIN=5.0V PWM

60

65

70

75

80

85

90

95

100

2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6VIN(V)

Effic

ienc

y (%

)

VOUT=1.0V PSAVE

VOUT=3.3V PSAVE

VOUT=3.3V PWM

VOUT=1.0V PWM

0

10

20

30

40

50

60

70

80

90

100

0.0001 0.001 0.01 0.1 1 10IOUT(A)

Effic

ienc

y (%

)

VIN=2.7V PSAVE

VIN=3.6V PSAVE

VIN=4.2V PSAVE

VIN=2.7V PWM

VIN=3.6V PWM

VIN=4.2V PWM

0

10

20

30

40

50

60

70

80

90

100

0.0001 0.001 0.01 0.1 1 10IOUT(A)

Effic

ienc

y (%

)

VIN=4.2V PSAVE

VIN=3.6V PSAVE

VIN=2.7V PSAVE

VIN=2.7V PWM

VIN=3.6V PWM

VIN=4.2V PWM

1.795

1.8

1.805

1.81

1.815

1.82

0 0.1 0.2 0.3 0.4 0.5 0.6IOUT(A)

V OU

T(V)

PSAVE ExitIOUT Increasing

VIN=3.6V, VOUT=1.8V

PSAVE EntryIOUT Decreasing

RFB1+RFB2=10KΩ RFB1+RFB2=10KΩ

RFB1+RFB2=10KΩ

IOUT=750mA (PWM) / 50mA (PSAVE), RFB1+RFB2=10KΩ

RFB1+RFB2=10KΩ


SC196


Load Regulation

VOUT

vs. Temperature VOUT

=1.8V Current Limit

Quiescent Current vs. Input Voltage, PSAVE Mode Quiescent Current vs. Input Voltage, PWM Mode

VOUT

vs. VIN

Typical Characteristics (Cont.)

1.76

1.77

1.78

1.79

1.8

1.81

1.82

2.4 2.8 3.2 3.6 4 4.4 4.8 5.2 5.6 6VIN(V)

V OU

T(V)

VOUT=1.8V, IOUT=750mA(PWM)/50mA(PSAVE)

PSAVE

PWM

1.785

1.79

1.795

1.8

1.805

1.81

1.815

1.82

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6IOUT(A)

V OU

T(V)

VIN=3.6V, VOUT=1.8V

PSAVE

PWM

1.778

1.78

1.782

1.784

1.786

1.788

1.79

1.792

1.794

1.796

1.798

-60 -40 -20 0 20 40 60 80 100TA(°C)

V OU

T(V)

VIN=3.6V, VOUT=1.8V, IOUT=100mA

PSAVE

PWM

12

13

14

15

16

17

18

19

20

21

22

2.5 3 3.5 4 4.5 5 5.5 6VIN(V)

Qui

esce

nt c

urre

nt (μ

A)

PSAVE Mode

TA=85°C

TA=25°C

TA=-40°C

3

3.5

4

4.5

5

5.5

6

2.5 3 3.5 4 4.5 5 5.5 6VIN(V)

Qui

esce

nt c

urre

nt (m

A)

PWM Mode

TA=85°C

TA=25°C

TA=-40°C

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4IOUT(A)

V OU

T(V)

VIN=3.6V, VOUT=1.8V, PWM


SC196


100% Duty Cycle Mode

PSAVE Operation PWM Operation

N-Channel RDSON

vs. Input Voltage

Switching Frequency vs. Temperature


P-Channel RDSON

vs. Input Voltage

0.10

0.15

0.20

0.25

0.30

0.35

0.40

2.7 3.2 3.7 4.2 4.7 5.2VIN(V)

TA=85°C

TA=25°C

TA=-40°C

950

960

970

980

990

1000

1010

1020

1030

1040

1050

-50 -30 -10 10 30 50 70 90 110 130

VIN=5.5V

TJ(°C)

Switc

hing

Fre

quen

cy (k

Hz)

VIN=3.6V

VIN=2.7V

Time (2μs/div)

VOUT (20mV/div)

ILX (200mA/div)

VLX (2V/div)

VIN=3.4V, VOUT=3.3V, IOUT=150mA, PWM

Time (2μs/div)

VOUT (50mV/div)

ILX (500mA/div)

VLX (2V/div)

VIN=3.6V, VOUT=1.8V, IOUT=150mA, PSAVE

Time (1μs/div)

VOUT (20mV/div)

ILX (500mA/div)

VLX (5V/div)

VIN=3.6V, VOUT=1.8V, IOUT=150mA, PWM

0.10

0.12

0.14

0.16

0.18

0.20

0.22

2.7 3.2 3.7 4.2 4.7 5.2VIN(V)

TA=85°C

TA=25°C

TA=-40°C

RD

SON(Ω

)

RD

SON(Ω

)


SC196


PWM Start-up

Load Transient Response-1



PSAVE Start-up



Time (100μs/div)

VEN (5V/div)

VOUT (1V/div)

IIN (100mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=10mA, PSAVE

Time (1ms/div)

VEN (5V/div)

VOUT (1V/div)

IIN (500mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=1.5A, PWM

Time (400μs/div)

VOUT (200mV/div)

IOUT (500mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=10mA to 1.5A, PWM

Time (400μs/div)

VOUT (200mV/div)

IOUT (500mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=100mA to 1.5A, PWM

Time (400μs/div)

VOUT (200mV/div)

IOUT (500mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=10mA to 1.5A, PSAVE

Time (400μs/div)

VOUT (200mV/div)

IOUT (500mA/div)

VIN=3.6V, VOUT=1.8V, IOUT=100mA to 1.5A, PSAVE


SC196


VOUT Programmed to 1.2V, no PSAVE

COUT10μF

L14.7μH

VIN2.5V to 5.5V

VOUT1.2V 1.5A

CIN10μF

VIN

EN

SYNC/PWM PGNDGND

MODE ADJ

SC196 LX RFB1

RFB2

VOUTPVIN 280k0.1%

200k0.1%

CFB110pF

Applications Circuits

The output voltage is set at 1.2V by the selection of the two resistors RFB1 and RFB2, using resistor values from Table 1. PWM-only mode operation is selected by connecting the SYNC/PWM pin to the VIN pin. The 100% duty cycle capability is selected by connecting the MODE pin to the VIN pin. A 10μF capacitor is selected for the output, as PSAVE operation is not required in this application.


SC196


MIN

aaabbb

b

eLN

DC

E

A1A2

A

DIM MILLIMETERSNOM

DIMENSIONS

MAXNOMINCHES

MIN MAX

.114 .118 .122 2.90 3.00 3.10

--

--

(LASER MARK)INDICATOR

PIN 1

1

N

2

NOTES:

CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).

COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS.2.

1.

.003

.007

.042

10

.009

.048

.000

.018

(.006)

0.08

0.23

10

.011

.052

0.18

1.06

.024

.002 0.000.45

1.31

0.30

1.21

0.05.60

(0.1524)

.004 0.10

0.50 BSC.020 BSC0.30.012 .020.016 0.40 0.50

A

aaa C

A2

SEATINGPLANE

A1

A

bxNbbb C A B

B

e

C

D

LxN

E

E

.074 .079 .083 1.87 2.02 2.12

C

Outline Drawing — MLPD-UT10 3x3x0.6


SC196


.087

.0552.201.40

.150

.020

.012

.0373.80

0.300.95

0.50

(.112).075 1.90

(2.85)

K

H

X

THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOURCOMPANY'S MANUFACTURING GUIDELINES ARE MET.

NOTES:1.

INCHESDIMENSIONS

G

KH

XY

P

Z

CDIM MILLIMETERS

Y

ZG(C)

P

2. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE


SC196


Land Pattern — MLPD-UT10 3x3x0.6

Semtech CorporationPower Management Products Division200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 FAX (805) 498-3804

Contact Information

www.semtech.com

SC196 1.5A Synchronous Buck Converter with …€¦ · 150 mV Output Voltage Range V OUT 0.8 V IN V...

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